[nolemmings]

Below is what I wrote back in 2017 when discussing the relative scarcity of m101 backs (in this case D352) for Old Cardboard:
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.oldcardboard.com/m/m101-4/schultz-2017-article/scarcity4b.pdf

[13th most common]The placement of Morehouse Baking here on the scarcity list should be noted with a disclaimer that it could change at the whim and caprice of a single collector. There are about 120 different subjects known to exist with this Lawrence, Massachusetts bakery back, but 3/4 of those are believed to be owned by one man, who shared scans of his grouping some years ago. That collection may have grown to include some of the other known examples, or may have decreased by unknown amounts if he has been disposed to parting with any. Although near sets of Gimbels and Herpolsheimer have been sold and apparently kept thereafter, decent numbers of those cards have circulated before and since. By contrast, excluding the singular collection of Morehouse cards leaves only 45-50 others confirmed in the hobby. Scarcity of this ad back is therefore very unstable, for it could change substantially on short notice.

Like Standard Biscuit, Morehouse Baking issued all cards from the m101-4 and m101-5 sets, meaning in theory there are twice as many cards that could carry this advertising. Thus far, the m101-4 version of these cards approximately doubles the number of known for m101-5. Morehouse Baking cards were subject to redemption and are often found with a purple “cancelled” stamp on the back, no doubt much to the chagrin of graded card collectors. No variations are known, either as to orientation or typeset, and no shortprinted cards have been identified.

Since then, around a dozen more subjects have been confirmed and I would correct my comments to say that there are slightly more m101-5 than m101-4 versions-- again, this is somewhat confusing because technically these should be referred to as D352-1 and D352-2.